An overview of time domain spectroscopy

An introduction outlining the operational use of time domain spectroscopy (TDS) is presented. As the most common use of TDS is the reflectance mode, attention is given to reflectance measurement techniques and analysis, specifically the application of a numerical algorithm to reduce the effects of the quarter and half wavelength resonant/anti-resonant conditions, and the use of bilinear correction analysis. The bilinear analysis method is described, using suitable permittivity standards, to obtain the complex bilinear coefficients used to correct data for imperfections in sampling head response, transmission lines, connector junctions, and the like. Reflectance measurements made on chlorobenzene are presented to demonstrate the effectiveness of this analysis in correcting the data for imperfections in the measuring system and extending the useful frequency range well beyond the `lumpʹ circuit frequency limit.